<?php
class Core_Data_Xssprotection implements  Core_Data_Mainable {
	
	public function main(array $variables = null){
		$value = $variables['value'];
		$value = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $value);
		$value= preg_replace('/(&#*w+)[x00-x20]+;/u', '$1;', $value);
		$value = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $value);
		// Fix &entity\n;
		$value = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $value);
		$value = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $value);
		$value = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $value);
		$value = html_entity_decode($value, ENT_COMPAT, 'UTF-8');
		
		// Remove any attribute starting with "on" or xmlns
		$value = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $value);
		
		// Remove javascript: and vbscript: protocols
		$value = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $value);
		$value = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $value);
		$value = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $value);
		
		// Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
		$value = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $value);
		$value = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $value);
		$value = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $value);
		
		// Remove namespaced elements (we do not need them)
		$value = preg_replace('#</*\w+:\w[^>]*+>#i', '', $value);
		
		do
		{
			// Remove really unwanted tags
			$old_data = $value;
			$value = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $value);
		}
		while ($old_data !== $value);
		
		// we are done...
		return $value;
	}
}